Crystallization of NaCl by fast evaporation of water in droplets of NaCl solutions

• Microcrystals are obtained by fast water evaporation from NaCl solutions.
• Size and shape of microcrystals depend on the process conditions.
• The dissolution rate of salt crystals is increased by reducing the crystal size.

Excessive salt (NaCl) intake has been related to several diseases. Small salt crystals that rapidly dissolve in the oral cavity may decrease swallowing of untasted salt. The aim of this research was to evaluate the crystallization of salt as microcrystals by fast water evaporation from droplets of saline solutions within a hot oil phase. The effects of the oil temperature (150; 165 and 180 °C), droplet volume (17 and 42 μL) and brine concentration (15 and 26% w/v) were studied. Crystalline particles with mean sizes between 9 and 23 μm, and containing about 2% of remaining oil were obtained. The crystal size decreased by increasing the oil temperature, solution concentration and volume of the droplets. The dissolution rate of these microcrystals was more than 2 times faster than that of the original crystals. The microcrystals obtained could be added in surface-salted foods (snacks, salads) to optimize or reduce the sodium intake while maintaining saltiness perception.

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